An ultrasonic transducer device typically includes a membrane capable of vibrating in response to a time-varying driving voltage to generate a high frequency pressure wave in a propagation medium (e.g., air, water, or body tissue) in contact with an exposed outer surface of the transducer element. This high frequency pressure wave can propagate into other media. The same piezoelectric membrane can also receive reflected pressure waves from the propagation media and convert the received pressure waves into electrical signals. The electrical signals can be processed in conjunction with the driving voltage signals to obtain information on variations of density or elastic modulus in the propagation media.
Ultrasonic transducer devices can be advantageously fabricated inexpensively to exceedingly high dimensional tolerances using various micromachining techniques (e.g., material deposition, lithographic patterning, feature formation by etching, etc.). As such, large arrays of transducer elements are employed with individual ones of the arrays driven via beam forming algorithms. Such arrayed devices are known as micromachined ultrasonic transducer (MUT) arrays and may utilized capacitive transducers (cMUTs) or piezoelectric transducers (pMUTs), for example.
Cross-talk between transducer elements can cause significant performance degradation of a MUT array and should therefore be minimized. One source of cross-talk is capacitive coupling. Such capacitive coupling may occur between signal lines of separate transducer channels within the array. MUT array architectures and structures that reduce such capacitive coupling are therefore advantageous.